5/18/2012 6:18:00 AM
1. Cell Structure and Cellular Metabolism
Textbook Human Physiology: From Cells to Systems. 2nd Canadian
Edition Chapter 2, pages 22-32
Principles of Cell Theory
Observation of Cells
Overview of Cell Structure
Substrate Level Phosphorylation
Electron Transport Chain
Cell theory: Life stems from the complex organization & interactions of the
chemicals within cells
All known living things are made up of cells
o The cell is the structural & functional unit of all living things.
o Cells are the living building blocks of whole bodies
All cells come from pre-existing cells by division (no
o Thus the cells of all organisms are fundamentally similar in
structure & function
o All cells are basically the same in chemical composition o All cells perform similar metabolic functions (some cells are
Cells contain hereditary information which is passed from
cell to cell during cell division.
o This is what allows for life to evolve. Evolution is done here.
Allows for mutation and evolution
For those interested:
Cells are small
The Discovery of Cells followed the invention of the
MICROSCOPE- cells werent known until we were able to see this
level with a microscope.
o Compound microscope- a series of lenses
One of the first compound microscopes created by the end of
16th century by Zacharias Janssen
o Hand-held microscope focus by sliding (like a telescope)
o Several lenses (i.e., compound )
o Magnifying images 3 to 10 times Cells divide instead of growing larger to LIMIT their Surface Area to Volume
Ratios. Cells need to be small because it makes their getting their food and
getting rid of wastes more efficient.
The SA of a cell is its cell membrane
Cells need a surface area large enough to allow adequate nutrients
to enter and rid itself of wastes
As cell gets larger, Vol increases faster than SA volume increases in
cubes while SA is squared.
SA increase 4X - but Vol increase 8X
SA/Vol ratio decreases
Less surface area for nutrient/waste diffusion
Cells get around this problem by:
Storing nutrients i.e., chicken egg can be bigger
Microvilli- may be found in the folds of the cell membrane. Made possible
when have greater surface area.
Overview of Cell Structure
Different cells share many common features
Cells in humans are highly organized structures that have 3
o Plasma membrane - encloses the cell
Selective barrier between cellular contents and
Regulates what comes in & leaves the cell
o Nucleus - Stores and encloses the DNA (genetic info)
protects DNA from the cytoplasm
Usually the largest organelle
o Cytoplasm - portion of cell interior NOT occupied by nucleus.
Organelles - distinct, highly organized, membrane-